This invention relates to a transport trailer of the general type disclosed in U.S. Pat. No. 6,047,989 which issued to the assignee of the present invention and the disclosure of which is herein incorporated by reference. This type of transport trailer is commonly used for transporting elongated agriculture equipment such as a removable and interchangeable head for a self-propelled combine. The trailer is pulled by a tractor or other vehicle and may have four wheel steering, for example, as disclosed in U.S. Pat. No. 3,806,160 and U.S. Pat. No. 7,874,571. In a trailer with four wheels steering, the front steering mechanism is controlled by a tow bar or tongue used to tow the trailer, and the rear steering mechanism is connected to the front steering mechanism by a connecting member or rod which extends longitudinally of the trailer. The steering mechanisms and the connecting rod causes the rear pair of wheels to turn in the same direction as the front pair wheels, for example, as disclosed in the above '160 and '571 Patents. When the front and rear cross frame members also function as axles to support the pivotal stub-axles for the front pair of wheels and rear pair of wheels, commonly the steering mechanism includes steering components which project below or adjacent the bottom surfaces of the frame members and are exposed to being impacted by an elevated railroad crossing or a rock or stump or other obstruction in a field and projecting upwardly from the ground. The impacting can damage a steering mechanism and/or connecting rod and require that the trailer be repaired or rebuilt. Damage to the steering mechanism or rod may also prevent the trailer from being used and require that the trailer be transported by a truck or another trailer to a facility for repair.